The present invention relates to a method of and an apparatus for advancing a filament. More particularly this invention concerns a yarn feeder usable for pulling a yarn off a supply, spinning apparatus, or similar source under a relatively constant tension.
Such a feeding apparatus is known which is rotatable about a main axis and which has an outer surface formed partially as a cylinder centered on this main axis and partially as a cylinder centered on a skew axis inclined at an acute angle to the main axis. The filament or yarn is fed tangentially to this rotating structure so as to initially impinge the rotating structure at the portion thereof centered on the skew axis, and is withdrawn tangentially from the arrangement of the surface portion centered on the main axis. The relative inclination of these two surface portions to each other insures that the filament will be urged axially along the assembly as it is wound thereon. This particular arrangement insures that the turns of the filament do not rub against each other and chafe. In particular when unspun yarns are being used such chafing can lead to filament breakage.
In one particular structure for achieving this end the two surfaces are formed by respective annular arrays of parallel rods that are angularly interleaved. Relatively complex bearing, support, and drive structure is provided to rotate the two arrays and achieve the desired results. Thus such arrangements are quite expensive. In addition lint build-up in such arrangements frequently leads to clogging and breakdown.
It is also known to form the rotating structure at least partially of radially and/or axially oscillating elements that insure the axial advance of the turns of the filament being advanced along the rotating drum. These devices are particularly complex and trouble prone, and when the tracks of the displaceable elements become fouled with the lint always present around such devices these arrangements invariably malfunction.
Prior-art devices can be seen in U.S. Pat. No. 3,225,446, German Pat. No. 1,635,899 and German Offenlegungschriften Nos. 1,942,062 and 2,126,845.